Thanks

Remove the bolt carrier from the upper. Remove the bolt from the carrier. Remove the ejector. Remove the extractor. Replace the ejectorless/extractorless bolt into the carrier. Insert the carrier back into the upper. Insert the Go gauge in the chamber. Gently push the carrier forward, it should close and lock on the Go gauge. Remove the Go gauge from the chamber. Insert the No Go gauge in the chamber. Gently push the carrier forward, it should not close and lock on the No Go gauge.

Assuming you have .223 headspace gauges. 5.56 military gauges are different. See the tacked headspace thread above for the details.

ETA your chamber, extension, bolt face and gauges should be squeaky clean for an accurate reading. We are talking about .001" or .0001" measurements (depending upon which gauges you have).

Why remove the extractor and ejector?

Quoted: Why remove the extractor and ejector?

the ejector will interfer with the guage and make it harder to determine if the bolt is closed or not.

simillar with the extractor.


ALSO, make sure the chamber is clean and dry (no lube) when you use your gauges.

Quoted: Quoted: Why remove the extractor and ejector? the ejector will interfer with the guage and make it harder to determine if the bolt is closed or not. simillar with the extractor. ALSO, make sure the chamber is clean and dry (no lube) when you use your gauges.

I thought you could simply look/feel that the bolt was not closed.   I have the 223 gauge set and you could see that the No-Go and the field guage did not allow the bolt to seat by looking that the back of the upper.    With the Go-Gauge the bolt was even too slightly recesed to the back of the upper.    Is there more to it than that?

Thanks

I do it because the directions say to. It only takes a minute to remove.

Maybe there are gauges out there that allow you to measure headspace without removing the extractor and ejector but the commonly used Forster and Clymer .223/5.56 gauges require removal.

Quoted: I thought you could simply look/feel that the bolt was not closed.   I have the 223 gauge set and you could see that the No-Go and the field guage did not allow the bolt to seat by looking that the back of the upper.   With the Go-Gauge the bolt was even too slightly recesed to the back of the upper.   Is there more to it than that? Thanks

Okay, are you saying it wouldn't close on a Go gauge?

I think you just answered your own question.

Or your chamber is too short.

ETA give it a try with the extractor and ejector removed. And clean the chamber, barrel extension and bolt face. It should close on a GO gauge. If it doesn't, you've got a problem.

We are talking about 1/10,000th of an inch. That's really tiny.

Quoted: Quoted: I thought you could simply look/feel that the bolt was not closed.   I have the 223 gauge set and you could see that the No-Go and the field guage did not allow the bolt to seat by looking that the back of the upper.   With the Go-Gauge the bolt was even too slightly recesed to the back of the upper.   Is there more to it than that? Thanks Okay, are you saying it wouldn't close on a Go gauge? I think you just answered your own question. Or your chamber is too short. ETA give it a try with the extractor and ejector removed. And clean the chamber, barrel extension and bolt face. It should close on a GO gauge. If it doesn't, you've got a problem. We are talking about 1/10,000th of an inch. That's really tiny.

No, it did close on the Go-Gauge.   It would not close on the No-Go and needless to say the field was a long way from closing.    Mine are also Forster so I will check out their instructions.    I was operation off of the build instructions in "the Ar-15 Complete Assembly Guide" by Walt Kuleck, Vol 2.  

Thank operatorerror.

No problem.